TomShea

I am experiencing a problem with the heater control in my 2002 LS 430. It has 125K miles on it. I just got it and assume it was not functioning when I purchased it. It was something I missed when inspecting the car. It takes a while for full heat to develop, engine cold start in MN winter. The first time I actually had the opportunity to drive it for more than a few minutes was today. The heater when on auto will continue to run fan full speed no matter what the temp is set for, and the inside temp continues to increase. One note is that the battery was just changed out and the compass had to be re-set following the instructions in the owners manual. I don't recall anything in the manual about this. It would be a pleasant suprise if it were something that simple, but I doubt I could be that lucky. Has anybody else experienced this?

Viper6

this sounds pretty normal... high fan speed until cabin reaches the temp you set... this takes awhile in cold starting ambient temps. Are you trying this at idle in the am... if you start driving right away the engine heats faster and should be able to shed that heat through the heater core and into your cabin quicker.

If it never reaches your set temp that is a real problem.

TomShea

Viper:
Thanks for your reply. I guess I was not clear with my symptoms. The heater continues to blow hot air well past the desired temp set. This is clearly a malfunction.

toyo

Stupid question, but are you sure you pushed the "Auto" button? Also, when the car is cold and you set it to 80 degrees does the fan motor blow cold air? If it does then that is a problem. It is designed to blow air only as the coolant temp rises.

TomShea

I guess I should have described the problem better. I was instead trying to explain how it was not initially evident. The few times I drove the car prior to discovering the probelm were too brief to allow full warm up of the engine. The problem became evident after the engine was fully warm. That is when it does not control the heat properly. The fan stays on high when on auto. This should gradually decrease when the selected temp is reached. Also the heat continues to increase in the car even after the selected temp is reached. It just continues to get hotter and hotter. This occurs even with the fan control on manual. The only way to control the temp is to turn off the unit or turn on the AC. Continually switching back and forth.

Viper6

Maybe a bad cabin or other air sensor? Not sure, likely electronic issue I would think... i'll see if there is anything in my manual for trouble shooting...

TomShea

I hope it's the cabin temp sensor. I went toa buddy's shop today and looked it up on All Data. The price shown for the part is $27. I would have to figure out how to get that panel off. The driver side lower dash panel. I am always afraid of breaking plastic parts when I'm pulling on them. I wonder if there are screws or if it's just a snap in.

Viper6

You need to get a manual... pays for itself the first time you don't screw up your car when you think you know what your doing... I hear wood parts are astronomical costs... don't break em! Manual shows where there are fasteners and how to remove...

Not to mention trouble shooting guides for issues like your that you are experiencing...

TomShea

Where do I get one?

TomShea

Thanks Viper, for sending me a private message on a source for service manuals.
I suspected the "Room temp sens" since without that functioning I could see the symtoms I was experiencing. Turns out the sensor was disconnected under the dash. There was also several fasteners missing. Someone had been in there and was not very careful about how they put it back together. So far now with a brief drive and some idling, I am satisfied that the climate control is functioning correctly. This is a relief, since there is one component listed on All Data for over $1200.00. I was willing to just change the room air temp out even if it tested OK, since it's only $27.00. I didn't have to do that. I hope that does not become an issue later. I didn't have the part at the time anyways.

warminwisc

Go team go!! Only on CL!